Apparatus for yarn severing in circular knitting machines



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P. A. MAHLER 3,225,571

YARN SEVERING IN CIRCULAR KNITTING MACHINES 3 Sheets-Sheet 1 J6 1 "A? 2! a 5/ Y4\ I i n h F. {Z 5/ 26 Mi H1 Q- I III 7 fl 75' W 11/ W 2Y4 BY PETER A. MAHLER ATTYS,

Dec. 28, 1965 P. A. MAHLER 3,225,571

APPARATUS FOR YARN SEVERING IN CIRCULAR KNITTING MACHINES Filed July 12, 1960 FEE) 79 3 Sheets-Sheet 2 I511 v ATT YS,

Dec. 28, 1965 P. A. MAHLER 3,225,571

APPARATUS FOR YARN SEVERING IN CIRCULAR KNITTING MACHINES Filed July 12, 1960 FEM].

3 Sheets-Sheet 3 IIIIIIIIIIIII INVENTORI PETER A. MAHLER BY United States Patent 3,225,571 APPARATUS FOR YARN SEVERING IN CIRCULAR KNITTING MACHINE Peter A. Mahler, Philadelphia, Pa., assignor, by mesne assignments, to The Singer Company, New York, N.Y.,

a corporation of New Jersey Filed July 12, 1960, Ser. No. 42,352 Claims. (Cl. 66-140) The present invention relates to circular knitting machines, and has particular application to means for severing the knitting yarns closely adjacent the needle circle in a multifeed machine.

The present invention is an improvement upon the yarn trimmers for rotary circular knitting machines in which a cutter element at a fixed location cooperates with a toothed ring mounted on the rotary dial of the knitting machine Within and closely adjacent the needle circle. Such cutting devices have not been entirely satisfactory on multifeed machines in which yarns are inserted into and withdrawn from action selectively at the different feed stations. The primary difiiculty resides in the proper locking-in of the free yarn end which is severed when the knitting of yarn at one station is terminated or initiated, inasmuch as a cutter of the type described does not provide a tail of yarn of sufficient length to prevent its raveling prior to being knitted-in and interlocked with the knitted loops of the subsequent course.

With the foregoing in mind, the present invention provides an improved cutter for a multifeed circular knitting machine in which the cutter operates to sever the yarn closely adjacent the needle circle at a position wherein the severed end of yarn is entrapped in the hook of the needle by the latch thereof, the cutting device being inoperative to cut the yarn end until it has been trapped in the needle hook by the latch.

More particularly, the present invention provides an improvement in cutters of the stated type wherein the cutter is positioned relative to the needle cams following the point where the cams lower the needles to an extent as to raise the latches.

More specifically, in accordance with a preferred embodiment of the present invention, the cutting mechanism which operates with the toothed ring to sever the yarn from one feed station, is located in registry with the stitch cam at the next subsequent feed station so as to cut the yarn end from the first feed station concurrently with the elevation of the latch of the needle at the subsequent feed station whereby the latch entraps the yarn end in the hook of the needle as the needle is depressed to the stitch-draw level.

The preferred embodiment of the present invention permits the cutting element to be located at the subsequent feed station in a position where it is inoperative upon the yarn ends being inserted and withdrawn at the subsequent feed station but is fully effective to sever the yarns from the first-mentioned feed station.

All of the objects of the present invention are more fully set forth hereinafter with reference to the accompanying drawings which illustrate circular knitting machines in accordance with the present invention, and wherein:

FIG. 1 is a fragmentary plan view showing the dial of a multifeed knitting machine along with a main and auxiliary feed station, certain operating elements being "ice omitted for the pumose of clarity of illustration of the present invention;

FIG. 2 is an enlarged fragmentary view in side elevation of the dial, as seen from the line 2--2 of FIG. 1;

FIGS. 3 and 5 are fragmentary sectional views through the dial as taken on the lines 3-3 and 55 respectively of FIG. 1;

FIG. 4 is a fragmentary perspective view of a cutter element such as shown in FIG. 2;'

FIG. 6 is a view at a reduced scale similar to FIG. 2 and showing in broken lines the positions of the needle cams relative to the position of the cutting element shown in FIG. 2;

FIG. 7 is a fragmentary perspective view illustrating the operation of the cutter;

FIG. 8 is a view in side elevation of the elements shown in FIG. 7;

FIG. 9 is a fragmentary sectional view taken on the angled section line 9-9 of FIG. 1 with a yarn shown in full line-s to illuustrate the operation of the suction tube;

FIG. 10 is a view similar to FIG. 1 of a modified embodiment of the present invention;

FIGS. 11 and 12 are enlarged sectional views taken on the lines 1111 and 1212 of FIG. 10; and

FIG. 13 is a fragmentary perspective view of the mechanism shown in FIGS. 11 and 12.

Referring to the drawings, the knitting machine illustrated in FIGS. 1 to 9 inclusive comprises a circle of needles 15 mounted for rotation in a needle cylinder 16 which carries a ring of sinkers 17 therewith (see FIG. 3). Within the needle circle 15, a rotary dial 21 is mounted for rotation with the needle cylinder 16. The dial 21 mounts a series of bitts 22 for radial projection therefrom and also mounts an annular ring 23 which, as shown in FIGS. 1, 2, and 4, is toothed about its periphery to provide a series of teeth 24 having radial leading faces 25 terminating at their upper edge in a cutting edge 26. A stationary dial cap 31 is mounted on the dial 21 and carries cutting elements and guide pins as more fully set forth hereinafter.

Surrounding the needle circle 15 is a latch ring 32 which is interrupted at a plurality of locations by feed stations, in the present instance designated 33 and 34. The feed station 33 comprises a throat plate 35 and a plurality of feed fingers 36. The feed station 34 comprises a throat plate 37 and a plurality of feed fingers 38. In accordance with the usual practice, the needle cylinder and dial are rotated and the feed fingers 36 and 38 are operated in timed relation to the needle cylinder 16 to insert yarns into and withdraw yarns out of action by the conventional pattern mechanism (not shown) including a pattern drum and pattern chain. Suction tubes 39 and 40 respectively overlie the dial to tension the yarns which are out of action and to Withdraw from the dial the yarn ends which are severed as described more fully hereinafter.

In accordance with the invention, a cutter mechanism is provided for each feed station, as designated generally at 28 and 29. Each of the cutter mechanisms 28 and 29 cooperates with the cutting edges 26 of the toothed ring 23 to sever the yarn engaged over the edge 26. The cutter mechanism 28 for the feed station 33 operates to cut only the yarns which are inserted or withdrawn at the feed station 33 and is inoperative to cut the yarns inserted and withdrawn at the feed station 34. By the same token, the cutter mechanism 29 for the feed station 34 is operative to out only the yarns inserted and withdrawn by the feed fingers 38 and is inoperative to sever the yarns inserted and withdrawn by the feed fingers 36 at the feed station 33.

In the embodiment of the invention illustrated in FIGS. 1 to 9 inclusive, the cutter mechanism 28 includes a flat spring element 44 mounted at one end on a bracket 45 which, in turn is secured to the dial cap 31. The flat spring element 44 extends circumferentially of the dial cap and at its free extremity terminates in a downturned leg 46 which rides on the upper surface of the teeth 24 of the toothed ring 23. As shown in FIG. 1, the leg 46 constitutes the cutter blade which engages the toothed ring 23 at a point slightly in advance of the feed station 34, so that the yarns inserted and withdrawn at the feed station 34 are not subject to severing by the leg 46 of the spring element 44.

In the operation of the cutter mechanism 28, the yarn Y-l that is withdrawn from action, for example by the feed finger 36-2, is carried by the needle circle and the toothed ring 23 into engagement with the leg 46 of the cutter element 44. As shown in FIG. 1, the yarn Y-1 passes over the dial cap in a generally straight-line path between the leg 46 of the cutter element 44 and the withdrawn feed finger 36-2. As shown in FIG. 1, the yarn passes under the cutter element 44 and bracket 45, under the outermost corner of the suction tube 39 under the hold-down wire 48 and upwardly to the elevated feed finger 36-2. When the leg 46 cooperates with the cutting edge 26 of the tooth, the yarn Y-l is severed and the suction in the tube 39 draws the severed end upwardly into the tube and the yarn Y-1 will thereafter assume a position adjacent the other inactive yarns Y-2 extending from the inactive feed fingers 36 to the tube 39. It should be noted that the elongated form of the nozzle tube 39 positions the inactive yarns Y-2 away from the path of movement of the yarns Y-1 and Y-3 across the top of the dial, and therefore prevents any interference between the inactive yarns and the yarns being inserted and withdrawn.

A yarn Y-3 was inserted into action by the feed finger 36-1 prior to withdrawal of the yarn Y-l. The yarn Y-3 was inserted by actuating the feed finger 36-1 to draw the yarn downwardly from the tube 39 into the needle circle 15. It is noted that the cutter mechanism 29 is positioned below the inactive yarns Y-Z, so that there is no possibility of the mechanism 29 severing the latter yarns. As the needle circle is rotated, it carries the yarn circumferentially around the dial cap, the suction in the tube 39 causing the yarn to assume a straight-line path between the tube 39 and the point of insertion of the yarn in the needle circle 15. FIG. 9 illustrates the yarn Y-3 in an intermediate position adjacent the suction tube 39. As the needle circle rotates the point of engagement beyond the intermediate position, the end of the yarn Y-3 is carried into engagement with the depending leg 46 of the cutter element 44, the yarn spanning from the cutting edge 26 of the tooth 24 under the element 44 and into the suction tube 39. When the tooth 24 is advanced past the depending leg 46, the yarn end is severed and the severed terminal end of the yarn Y-3 is carried away by the suction tube 39, leaving a very small tail. Since the operation of the knitting machine provides an overlap between the withdrawn yarn end and the inserted yarn end, there is no substantial problem in providing an effective lock-in of the severed yarn ends, from the feed station 33, and the cutter mechanism 28 may be positioned at any location where it is inoperative upon the yarns inserted at the feed station 34, but is operative upon the yarns inserted or withdrawn at the feed station 33.

In accordance with one feature of the invention, the cutter meuhanism 29 for the auxiliary feed station 34 is positioned at the next subsequent feed station in a position where the latches of the needles are in position to trap the severed yarn end within the hooks of the needles. To this end, the cutter mechanism 29 is positioned adjacent the main feed station 33. As shown in FIG. 2, the cutter mechanism 29 comprises a flat spring member 51 having at its free extremity a depending leg 52 which cooperates with and bears upon the teeth 24 of the ring 23. At its opposite end, the cutter member 51 is mounted at a point in registry with the feed fingers 36 in a bracket 52a having a yarn deflector 53 formed integrally therewith. The yarn deflector 53 insures that the yarns from the feed fingers 38 pass under the cutter element 51 so as to be severed by the engagement of the leg 52 with the teeth 24.

In the operation of the cutter 29, as shown in FIGS. 1 to 8, the yarn Y-4 is shown being withdrawn from action by the feed finger 38-2. The Y-5 has been inserted into action by the feed finger 38-3 and the yarn Y-6 is held out of action by the feed finger 38-1. As shown in FIG. 1, the yarns Y-4 and Y-6 pass under a hold-down wire 56 and are elevated above the top surface of the dial cap 31 intermediate the feed station 34 and the suction tube 40 by an elevator wire 57 (see FIG. 5) which reduces the drag on the yarn and assists the tensioning of the yarn by the suction tube 40, the yarns passing around guide pins 58, 59 and 60 which prevent entanglement of the yarn with the mechanism on the dial. The elevator wire 57 is mounted on the dial cap 31 and has, in the present instance, a series of spaced portions each disposed transversely of the path of the yarns Y-4 and Y-6, and underlying said yarns between the feed station 34 and the end of the suction tube 40, whereby the yarns are elevated to reduce the drag thereon so that the tension applied to the withdrawn yarns Y-4 and Y-6 by the suction tube after severance is effective to maintain proper tension on said yarns at the feed station 34. The yarn Y-6 is drawn up into the suction tube 40 and the yarn Y-4 continues around the dial, being guided by pins 61, 62, and 63 and is finally carried under the cutter element 51 by the needle circle 15 and the toothed ring 23. It is noted the final group of needles designated 15-4 in FIGS. 1, 7 and 8 are not depressed to the stitch-draw level at the feed station 34, so that they carry the yarn Y-4 within their open hooks which receive the yarn Y-3 at the feed station 33, thereby forming composite loops on the needles 15-4. This is more fully set forth in my copending application Serial No. 692,670, now US. Patent No. 2,987,900 of June 13, 1961.

As shown in FIG. 6, the cutting leg 52 of the cutter element 51 is positioned in registry with the stitch cam which depresses the needles 15 to the stitch-draw level. The needles 15 are conventional latch needles having a hook 71, and a latch 72 pivoted thereto. As the pivot point of the latch 72 passes from above to below the sinker level 17, the previously knit loop of the yarn Y-5 on the needles 15 raises the latch to close the hook 71 in conventional manner. As clearly shown in FIG. 8, the positioning of the leg 52 in registry with the stitch cam insures that the latch 72 is closed against the hook 71 when the yarn end Y-4 is severed. By this arrangement, therefore, the severed end of the yarn Y-4 is entrapped in the needle hook 71 and a proper lock-in of the trailing end of the yarn Y-4 is provided. Upon severance of the yarn Y-4, the suction tube 40 draws the severed unknit end of yarn away from the cutter element 51 and into the tube where it assumes a position adjacent the yarn Y-6.

A similar action occurs when the yarn Y-S is carried by the needle circle 15 and the toothed ring 23 into engagement with the cutter element 51. The yarn Y-5 at this point spans from the cutter element 51 around the guide pins 63, 62, and 61 and into the suction tube 40. When the yarn passes the depending leg 52 of the cutter element, it is severed and the severed end is withdrawn from the dial by the suction in the tube 40. The knit end of yarn, as was the casein connection with yarn Y-4, is trapped in the hooks 71 of the needles 15 by the latches 72 and the positioning of the cutter element at the stitch cam of the subsequent feed station therefore insures proper locking-in of the yarn end.

It is noted that an initial group of needles designated 15-5 in FIG. 1 are not depressed to the stitch-draw level at the station 34, so that they carry the yarn Y5 within their open hooks which receive the yarn Y-3 at the feed station 33. This action is set forth more fully in my above-noted patent.

It is apparent that if desired, the cutter mechanism 29 may be positioned further along on the needle cam track if means is provided to insure that the cutter mechanism 29 does not sever the yarns inserted and withdrawn at the feed station 33. For the purposes of this invention, it is preferred to locate the cutting element 52 of the cutter 51 in registry with the stitch cam 70 in the position where the needle latches 72 are elevated to close the hooks 71 of the needles and prevent escape of the severed yarn end from the hooks. By the location of the cutting element 52 at this location, the yarn Y-3 which is inserted at the feed station 33 is drawn down into the teeth 24 of the ring 23 by the stitch cam 70 immediately after passing over the cutter blade 51.

Another form of cutter mechanism is illustrated in FIGS. to 13 inclusive. In this embodiment of the inention, a cutter mechanism 128 is substituted for the cutter mechanism 28 of the previously described embodiment.

The cutter mechanism 128 comprises a cutter blade 130 mounted in a holder 131 which is pivoted to a mounting bracket 132 as indicated at 133. The mounting bracket 132, in turn, is pivoted to the dial cap adjacent the central post thereof as indicated at 134, the weight the bracket causing it to rest on the upper surface of the dial cap. A biasing spring 135 is tensioned between the mounting bracket 132 and the holder 131 to urge the blade 130 into engagement with the toothed ring 23, the displacement of the holder 131 being limited by a limit pin 136 threadably engaged with the holder and bearing against the bracket 132. An operating lever 138 is engaged with the holder 131 and is operable to elevate the blade 130 out of engagement with the toothed ring 23, as shown in broken lines in FIG. 12 when the lever 138 is actuated by the pattern mechanism of the knitting machine.

In the operation of the cutter mechanism 128, the operating lever 138 is actuated to elevate the blade 130 when yarns inserted at the feed station 34 are carried by the needle circle 15 and the toothed ring 23 past the cutter 128 so that the cutter does not sever the latter yarns and they are carried around to the cutter mechanism 29 for severing when the latches of the needles are raised to entrap the severed yarn within the books of the needles. The lever 138 is actuated to engage the blade 130 against the toothed ring 23 whenever yarns are inserted and withdrawn at the feed station 33, and said yarns are carried into registry with the cutter mechanism 128. The cutter mechanism therefore permits the yarns inserted and with drawn at the feed station 33 to be severed at the cutter mechanism 128, and the yarns inserted and withdrawn at the feed station 34 to be severed at the cutter mechanism 29. It is noted that the yarns severed by the cutter mechanism 128 have been interknit with the succeeding course at the feed station 34 so that there is no possibility of improper locking-in of the severed yarn end.

If desired operating levers similar to the lever 138 may be provided for the cutter elements 44 and 51 to disengage the legs 46 and 52 from the toothed ring 23 when there is no insertion or withdrawal of yarns at the respective feed stations 33 and 34.

While a particular embodiment of the present invention has been herein illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.

What I claim is:

1. In a multifeed circular knitting machine having a rotary cylinder mounting a needle circle, a toothed ring mounted for rotation with said cylinder adjacent to and within said needle circle, a stationary dial cap superim: posed on said ring, and at least two feed stations having feed fingers operable between active and inactive positions to respectively introduce yarn into and withdraw yarn from said needle circle and needle cams to actuate said needles to the stitch-draw level; a cutter for yarn inserted and withdrawn at at least one feed station comprising a cutter blade mounted on said dial cap and cooperative with said toothed ring to sever the yarn, said cutter blade contacting said toothed ring beyond the feed fingers of a subsequent feed station and in registry with said needle cam actuating the needles to stitch-draw level at said subsequent feed station, to thereby sever the yarn inserted and withdrawn at said one feed station following actuation of the needles at said subsequent feed station, said cutter being inoperative to sever the yarn inserted and withdrawn at said subsequent feed station.

2. Apparatus according to claim 1 wherein said cutter comprises an elongated flat spring element secured at one end to the dial cap at a point in registry With the feed fingers at said subsequent feed station, extending circumferentially of said dial cap, and terminating at the other end in a downwardly-dependin g leg contacting said toothed ring and constituting the aforesaid cutter blade, whereby the yarns inserted and withdrawn at said subsequent feed station pass above said spring 'blade, the yarns inserted and withdrawn at said one feed station passing between said element and cutter blade and said toothed ring to be severed thereby.

3. Apparatus according to claim 1 including a second cutter for yarns inserted and withdrawn at the subsequent feed station, said cutter comprising a spring blade mounted on said dial cap and having 21 depending leg engaging the toothed ring intermediate said subsequent feed station and said one feed station to thereby sever the yarns inserted and withdrawn at said subsequent feed station without severing the yarns inserted and withdrawn at the one feed station.

'4. In a multifeed circular knitting machine having a rotary cylinder mounting a needle circle, a toothed ring mounted for rotation with said cylinder adjacent to and within said needle circle, a stationary dial cap superimposed on said ring and at least two feed stations having feed fingers operable between active and inactive positions to respectively introduce yarn into and withdraw yarn from said needle circle and needle cams to actuate said needles to the stitch-draw level; a first cutter for yarn inserted and withdrawn at the first feed station comprising a cutter blade mounted on the dial cap and cooperative with said toothed ring to sever the yarn, said cutter blade contacting said toothed ring in registry with the needle cam actuating the needles to stitch-draw level beyond the feed fingers of a subsequent feed station to sever the yarn inserted and withdrawn at said first feed station following actuation of said needles at said subsequent feed station, said cutter being inoperative to sever the yarn inserted and withdrawn at said subsequent feed station, a second cutter for yarns inserted and withdrawn at said subsequent feed station, said second cutter comprising a cutter blade mounted on said dial cap for pivotal displacement into and out of engagement with said toothed ring, and means biasing said blade into engagement with said ring.

5. Apparatus according to claim 4 wherein said second cutter is positioned intermediate said one and said subsequent feed stations, said cutter including an actuating lever to displace said blade from engagement with said toothed ring when the yarn from the one feed station is passing therebetween to thereby avoid severing said yarn by said second cutter.

(References on following page) UNITED 7 References Cited by the Examiner 3,097,512 3,097,513 STATES PATENTS Page 6642 219,666 MIHCT 5 Stack et a1. 66140 Butler 66140 Peel 66-140 8 7/1963 Moyer 66145 X 7/1963 Pike et a1. 66145 FOREIGN PATENTS 1/ 1959 Australia. 5/1959 Italy.

RUSSELL C. MADER, Primary Examiner. MERVIN STEIN, Examiner. 

1. IN A MULTIFEED CIRCULAR KNITTING MACHINE HAVING A ROTARY CYLINDER MOUNTING A NEEDLE CIRCLE, A TOOTHED RING MOUNTED FOR ROTATION WITH SAID CYLINDER ADJACENT TO AND WITHIN SAID NEEDLE CIRCLE, A STATIONARY DIAL CAP SUPERIMPOSED ON SAID RING, AND AT LEAST TWO FEED STATIONS HAVING FEED FINGERS OPERABLE BETWEEN ACTIVE AND INACTIVE POSITIONS TO RESPECTIVELY INTRODUCE YARN INTO AND WITHDRAW YARN FROM SAID NEEDLE CIRCLE AND NEEDLE CAMS TO ACTUATE SAID NEEDLES TO THE STITCH-DRAW LEVEL; A CUTTER FOR YARN INSERTED AND WITHDRAWN AT AT LEAST ONE FEED STATION COMPRISING A CUTTER BLADE MOUNTED ON SAID DIAL CAP AND COOPERATIVE WITH SAID TOOTHED RING TO SEVER THE YARN, SAID CUTTER BLADE CONTACTING SAID TOOTHED RING BEYOND THE FEED FINGERS OF A SUBSEQUENT FEED STATION AND IN REGISTRY WITH SAID NEEDLE CAM ACTUATING THE NEEDLES TO STITCH-DRAW LEVEL AT SAID SUBSEQUENT FEED STATION, TO THEREBY SEVER THE YARN INSERTED AND WITHDRAWN AT SAID ONE FEED STATION FOLLOWING ACTUATION OF THE NEEDLES AT SAID SUBSEQUENT FEED STATION, SAID CUTTER BEING INOPERATIVE TO SEVER THE YARN INSERTED AND WITHDRAWN AT SAID SUBSEQUENT FEED STATION. 